Determination of Residues of Four Succinate Dehydrogenase Inhibitor Fungicides in Beef by Gas Chromatography- Tandem Mass Spectrometry

A method for the determination of residues of four succinate dehydrogenase inhibitor fungicides including penthiopyrad, penflufen, pydiflumetofen and benzovindiflupyr in beef by gas chromatography-tandem mass spectrometry (GC-MS/MS) was proposed. The ground beef sample (5 g) was extracted twice with 10 mL of cyclohexane and ethyl acetate mixed solution at volume ratio of 1∶1, and purified with 2.0 mL of acetonitrile. An aliquot (1.0 mL) of acetonitrile layer was taken, and blown to nearly dryness in water bath by nitrogen at 40 ℃, and the remaining residue was dissolved with 1.0 mL of n-hexane. The obtained solution was filtrated by 0.22 μm organic filter membrane, and the filtrate was determined according to the operating conditions of the instrument. Four succinate dehydrogenase inhibitor fungicides were separated by column temperature program, and detected by multiple reaction monitoring mode. The working curves were drawn by matrix matching method, and external standard method was used for quantitative analysis. It was shown that the linear ranges of four succinate dehydrogenase inhibitor fungicides were 0.2-20.0 μg·L^-1, with detection limits (3S/N) of 0.08 μg·kg^-1. Test for recovery was made on the blank sample by standard addition method at 3 concentration levels, giving results in the range of 89.8%-105%, and RSDs (n=6) of the determined values ranged from 0.74% to 4.5%. The method was used to analyze 12 actual samples, and the targets were not detected.